1. Technical Field
The present invention generally relates to bag filling and sealing apparatus and, more particularly to the assemblies of these apparatus that hold the bags while the bags are filled or sealed. Specifically, the present invention relates to an assembly that aligns the flanges on the sides of a bag so that the flanges may be grasped by gripping jaws.
2. Background Information
Packaging various items in plastic bags is becoming increasingly popular in the packaging and food packaging industry. Plastic bags are inexpensive to manufacture and have the ability to keep food fresher than other types of traditional packaging. Some types of plastic bags may include a resealable closure. Problems have occurred in the food industry in filling these bags leading some packaging companies to fill the bags by hand. Filling bags by hand is expensive and increases the probability of food contamination.
One prior art apparatus that automatically fills and seals these bags is disclosed in application Ser. No. 09/698,830 filed Oct. 27, 2000 owned by the assignee of this application. This apparatus uses fingers that pinch the upper corners of the bag. One of the fingers is thus inserted into the bag when the corners are pinched. After the bag is filled, the upper portion of the bag is removed as a waste strip. The art desires a bag grasping assembly that holds the bag by the flanges of the bag with no portion of the grasping assembly being positioned in the bag.
One problem with grasping the flanges of the bag is that the flanges are often flat against the sidewall of the bag when the flanges must be grasped. The art desires a flange-grasping assembly that positions the flanges in an extending grasping position just before the grasping assembly arrives to clamp the flange. The art also desires an assembly that can reliably grasp the flanges while eliminating essentially all misses to increase the efficiency of the apparatus.
The invention provides a flange alignment and grasping assembly that is adapted to straighten the flanges of a bag in a filling and sealing apparatus so that the flanges may be clamped by the assembly. The assembly includes opposed guides that engage the side of the bag in the general location of the flange. The guides position the flange in an extended position between the jaws of a clamp where the clamp will pinch the flange when the clamp closes.
Different embodiments of the guides are disclosed with the guides having different shapes and different mounting locations.
The invention also provides an apparatus for grasping a bag and pulling a portion of the bag tight. The apparatus includes arms that swing upwardly and inwardly to engage the flanges of the bag. Portions of the arms then move outwardly to pull the bag tight.